Re: [Lsr] Request WG adoption of TTZ

I also support the adoption of TTZ draft.

The Virtual Zone concept would be very useful for the Overlay networks. The proposed TTZ can group a set of nodes not geographically together into one virtual area to scale virtual overlay networks with lots of nodes. Those kind overlay networks are getting more momentum in SDWAN and CDN environment.

Linda Dunbar

From: Lsr <lsr-bounces@ietf.org> On Behalf Of LEI LIU
Sent: Friday, July 10, 2020 12:42 PM
To: Huaimo Chen <huaimo.chen@futurewei.com>
Cc: lsr@ietf.org; lsr-chairs@ietf.org
Subject: Re: [Lsr] Request WG adoption of TTZ

I support the adoption of the TTZ draft.

The operation on TTZ is simple. Smooth transferring between a zone and a single node will improve customer experience. The work on TTZ should be moved forward.

Thanks,
Best regards,

Lei

On Thu, Jun 18, 2020 at 8:38 PM Huaimo Chen <huaimo.chen@futurewei.com<mailto:huaimo.chen@futurewei.com>> wrote:

Hi Chris and Acee, and everyone,

    I would like to request working group adoption of "Topology-Transparent Zone"

(TTZ for short) https://datatracker.ietf.org/doc/draft-chen-isis-ttz/<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fdraft-chen-isis-ttz%2F&data=02%7C01%7Clinda.dunbar%40futurewei.com%7Cf4502b794e7a4b66836408d824f8c059%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C637299998093803058&sdata=tqunOWC7trBoFu3XBvAFrLDzyFdlLQl9xYMtMdPSMgo%3D&reserved=0> .

    This draft comprises the following solutions for helping to improve scalability:

        1) abstracting a zone to a single pseudo node in IS-IS,

        2) abstracting a zone to a single pseudo node in OSPF,

        3) abstracting a zone to zone edges' full mess in IS-IS, and

        4) transferring smoothly between a zone and a single pseudo node.

    A zone is a block of an area (IS-IS L2 or L1 area, OSPF backbone or

non-backbone area).

    When a network area becomes (too) big, we can reduce its size in the sense

of its LSDB size through abstracting a zone to a single pseudo node or

abstracting a few zones to a few pseudo nodes.

    While a zone is being abstracted (or transferred) to a single pseudo node,

the network is stable. There is no or minimum service interruption.

    After abstracting a few zones to a few pseudo nodes, if we want to reconstruct

them, we can transfer (or roll) any of the pseudo nodes back to its zone smoothly

with no or minimum service interruption.

    We had a prototype implementation of abstracting a zone to zone edges' full

mess in OSPF. The procedures and related protocol extensions for transferring

smoothly from a zone to zone edges' full mess are implemented and tested.

A zone (block of an OSPF area) is smoothly transferred to its edges’ full mess

without any routing disruptions. The routes on every router are stable while

the zone is being transferred to its edges' mess. It is very easy to operate

the transferring.

    There are two other drafts for improving scalability: "Area Proxy for IS-IS"

(Area Proxy for short) and "IS-IS Flood Reflection" (Flood Reflection for short).

    "Area Proxy" https://tools.ietf.org/html/draft-li-lsr-isis-area-proxy-03<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftools.ietf.org%2Fhtml%2Fdraft-li-lsr-isis-area-proxy-03&data=02%7C01%7Clinda.dunbar%40futurewei.com%7Cf4502b794e7a4b66836408d824f8c059%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C637299998093808054&sdata=OxU3ikjVtGtL7piPPc2WJQ8GatTz1XMnoREwVA00%2F2E%3D&reserved=0>

abstracts an existing IS-IS L1 area to a single pseudo node.

    "Flood Reflection" https://tools.ietf.org/html/draft-przygienda-lsr-flood-reflection-01<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftools.ietf.org%2Fhtml%2Fdraft-przygienda-lsr-flood-reflection-01&data=02%7C01%7Clinda.dunbar%40futurewei.com%7Cf4502b794e7a4b66836408d824f8c059%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C637299998093818056&sdata=jiSeOvvxabugWULFhFag%2BvVHEbmXBF6mza9cSwbi5t8%3D&reserved=0>

abstracts an existing IS-IS L1 area to its edges' connections via one or more

flood reflectors.

    We believe that TTZ has some special advantages even though

Area Proxy and Flood Reflection are very worthy. We would like

to ask for working group adoption of TTZ.

Best Regards,

Huaimo
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